110 lines
2.5 KiB
NASM
110 lines
2.5 KiB
NASM
; ***************************************************************************
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; copyright : (C) 2025 by Martin Preuss
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; email : martin@libchipcard.de
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;
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; ***************************************************************************
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; * This file is part of the project "AqHome". *
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; * Please see toplevel file COPYING of that project for license details. *
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; ***************************************************************************
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; ---------------------------------------------------------------------------
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; @macro m_ringbuffer_writebyte
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;
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; @param R16 byte to write
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; @param %0 constant maxBytes
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; @param %1 address of usedBytes variable
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; @param %2 address of readPos variable
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; @param %3 address of writePos variable
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; @param %4 address of buffer
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; @return CFLAG set if okay, cleared on error (i.e. buffer full)
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; @clobbers R17, X
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.macro m_ringbuffer_writebyte
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ld r17, @1 ; usedBytes
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cpi r17, @0 ; maxBytes
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brcc l_end
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inc r17
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st @1, r17 ; usedBytes
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ld r17, @3 ; writePos
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ldi xl, LOW(@4) ; buffer start
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ldi xh, HIGH(@4)
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add xl, r17
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adc xh, r17
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sub xh, r17
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st X, r16
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inc r17
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cpi r17, @0 ; maxBytes
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brcs l_store
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clr r17
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l_store:
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st @3, r17 ; writePos
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sec
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l_end:
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.endmacro
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; @end
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; ---------------------------------------------------------------------------
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; @macro m_ringbuffer_readbyte
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;
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; @param %0 constant maxBytes
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; @param %1 address of usedBytes variable
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; @param %2 address of readPos variable
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; @param %3 address of writePos variable
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; @param %4 address of buffer
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; @return CFLAG set if okay, cleared on error (i.e. buffer full)
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; @return R16 byte read
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; @clobbers R17, X
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.macro m_ringbuffer_readbyte
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ld r17, @1 ; usedBytes
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tst r17
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clc
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breq l_end
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dec r17
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st @1, r17 ; usedBytes
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ld r17, @2 ; readPos
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ldi xl, LOW(@4) ; buffer start
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ldi xh, HIGH(@4)
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add xl, r17
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adc xh, r17
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sub xh, r17
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ld r16, X
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inc r17
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cpi r17, @0
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brcs l_store
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clr r17
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l_store:
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st @2, r17 ; readPos
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sec
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l_end:
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.endmacro
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; ---------------------------------------------------------------------------
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; @macro m_ringbuffer_reset
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;
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; @param %0 constant maxBytes
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; @param %1 address of usedBytes variable
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; @param %2 address of readPos variable
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; @param %3 address of writePos variable
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; @param %4 address of buffer
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; @clobbers R17
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.macro m_ringbuffer_reset
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clr r17
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st @1, r17 ; usedBytes
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st @2, r17 ; readPos
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st @3, r17 ; writePos
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l_end:
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.endmacro
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; @end
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